Đáp án:
Giải thích các bước giải:
a,4x2−4x−(1−x)=0a,4x2-4x-(1-x)=0
⇔4x(x−1)+(x−1)=0⇔4x(x-1)+(x-1)=0
⇔(x−1)(4x+1)=0⇔(x-1)(4x+1)=0
⇒x=1⇒x=1 hoặc x=−14x=-14
b,5x2+10x−4x−8=0b,5x2+10x-4x-8=0
⇔5x(x+2)−4(x+2)=0⇔5x(x+2)-4(x+2)=0
⇔(x+2)(5x−4)=0⇔(x+2)(5x-4)=0
⇒x=−2⇒x=-2 hoặc x=45x=45
c,x2+7x−4x−28=0c,x2+7x-4x-28=0
⇔x(x+7)−4(x+7)=0⇔x(x+7)-4(x+7)=0
⇔(x+7)(x−4)=0⇔(x+7)(x-4)=0
⇒x=4⇒x=4 hoặc x=−7x=-7
d,12x2−18x−3(16x−14)=0d,12x2-18x-3(16x-14)=0
⇔x2−14x−x+32=0⇔x2-14x-x+32=0
⇔x2−54x+32=0⇔x2-54x+32=0
⇔4x2−5x+6=0⇔4x2-5x+6=0
⇔4x2−2.2x.54+2516+7116=0⇔4x2-2.2x.54+2516+7116=0
⇔(2x−54)2+7116=0⇔(2x-54)2+7116=0 vô lý
=>pt vô nghiệm
e,x2+5x−6=0e,x2+5x-6=0
⇔x2−x+6x−6=0⇔x2-x+6x-6=0
⇔x(x−1)+6(x−1)=0⇔x(x-1)+6(x-1)=0
⇔(x−1)(x+6)=0⇔(x-1)(x+6)=0
⇒x=1⇒x=1 hoặc x=−6x=-6
g,x2−3x+2=0g,x2-3x+2=0
⇔x2−x−2x+2=0⇔x2-x-2x+2=0
⇔x(x−1)−2(x−1)=0⇔x(x-1)-2(x-1)=0
⇔(x−1)(x−2)=0⇔(x-1)(x-2)=0
⇒x=1⇒x=1 hoặc x=2x=2
h,2x2−4x+2=0h,2x2-4x+2=0
⇔2(x2−2x+1)=0⇔2(x2-2x+1)=0
⇔2(x−1)2=0⇔2(x-1)2=0
⇒x−1=0⇒x-1=0
⇒x=1
